This section is intended to introduce the reader to aspects of art that may be related to various aspects of the present disclosure described herein, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure described herein. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
A combine harvester is a machine that is used to harvest grain crops. The objective is to complete several processes, which traditionally were distinct, in one pass of the machine over a particular part of the field. Among the crops that may be harvested with a combine can include but is not limited to wheat, oats, rye, barley, corn, soybeans, and flax or linseed. The waste (e.g., straw) left behind on the field includes the remaining dried stems and leaves of the crop having limited nutrients which may be, for example, chopped and spread on the field or baled for feed and bedding for livestock. Generally, the combine harvester includes a header, which removes the crop from a field, and a feeder housing which transports the crop matter into a threshing rotor. The threshing rotor can include one or more rotors which can extend axially (front to rear) or transversely within the body of the combine, and which are partially or fully surrounded by one or more perforated concaves. In particular, the there may be a rotor having concave bars and grates for threshing operations of the crop, and another concave grate having fingers for separation operations of the crop material, also known as separation concaves or separation grates. Generally, the separation grate is meant to separate any grain that is caught in material other than grain, such as chaff, shucks, stalk, leafy material, among others, which may also be referred to herein as MOG.
Here, the concave and separator grate assemblies can be arranged side-by-side axially along the processing system of a combine harvester. The crop material is threshed and separated by the rotation of the rotor within the concave. Coarser non-grain crop material such as stalks and leaves are transported to the rear of the combine and discharged back to the field. The separated grain, together with some finer non-grain crop material such as chaff, dust, straw, and other crop residue can be discharged through the concaves and fall onto a grain pan where they are transported to a cleaning system.
However, current conventional concave bars and separation grates have certain configurations that are not optimized to maximize threshing and separating of the crop material, thereby resulting in inefficient harvesting and wasted crop. In one example of conventional combine concaves, if a combine harvester has three concaves, then a crop that is threshed in a first concave can still be threshed by the other two concaves behind it, or a ⅔ probability for the crop grains to fall through the concave openings before it is discharged to the back and out of the combine. However, if the crop does not get threshed until the second concave, then it has a ⅓ probability for it to be threshed before it reaches the third concave. Further, if the crop is not threshed in the second concave, then the third concave can become overloaded with crop and grain material and operating at over capacity, thus resulting in the grain being discharged out the back of the combine and resulting in very inefficient harvesting.
What is needed is a concave bar configuration that is optimized to certain threshing angles for its bars to maximize a threshing surface area of crop material and minimize the time needed to thresh the crop, such that seed or grain has more efficient and quickly fall through the openings of the concave, thereby minimizing or eliminating wasted crop material, among others. What is also needed is a more efficient separation grate that provides full separation of the grain, maximizes separation capacity of the combine, and more effective agitation of the crop and grain material, thereby maximizing harvesting efficiency, among others.